1. Sibley CG, Monroe BL Jr (1990). Distribution and Taxonomy of Birds of the World. New Haven, Connecticut: Yale University Press.
2. Sibley CG, Monroe BL Jr (1993). A Supplement to Distribution and Taxonomy of Birds of the World. New Haven, Connecticut: Yale University Press.
3. Gill FB (1995). Ornithology, 2nd edn. New York: WH Freeman and Co.
4. Bennett PM, Owens IPF (2002). Evolutionary Ecology of Birds. Life Histories, Mating Systems and Extinction. Oxford: Oxford University Press.
5. Dunning JB Jr (1992). CRC Handbook of Avian Body Masses. Boca Raton, Florida: CRC Press.